BasisFeatureDate (FIX tag 259)

LocalMktDateFIX 4.4

BasisFeatureDate (tag 259) is a LocalMktDate field defined in FIX 4.4. It appears in 1 message type, always optionally.

At a glance

Tag: 259
Name: BasisFeatureDate
Datatype: LocalMktDate (String)
Format: YYYYMMDD
Dialects: FIX 4.4
Messages: 1

What the specification says

BasisFeatureDate allows requesting firms within fixed income the ability to request an alternative yield-to-worst, -maturity, -extended or other call. This flows through the confirm process. (Note tag # was reserved in FIX 4.1, added in FIX 4.3) (prior to FIX 4.4 field was of type UTCDate)

Descriptions are quoted from the FIX Orchestra sources under the Apache 2.0 licence.

A real message using tag 259

ExecutionReport · FIX 4.4

Tag	Field	Wire value	Meaning
8	BeginString	FIX.4.4
9	BodyLength	146
35	MsgType	8	Execution Report
49	SenderCompID	BOARTEAM
56	TargetCompID	COUNTERPARTY
34	MsgSeqNum	2
52	SendingTime	20240101-12:00:00.000
37	OrderID	ORD-10042
17	ExecID	EXEC-88117
150	ExecType	0	New
39	OrdStatus	0	New
54	Side	1	Buy
151	LeavesQty	0
14	CumQty	1000000
6	AvgPx	1.09215
259	BasisFeatureDate	20240101
10	CheckSum	133

Edit and decode it yourself

Shown with | separators for readability. On the wire FIX uses SOH (0x01), an invisible control byte — and because BodyLength and CheckSum are computed over the actual bytes, the two forms have different checksums. Both are valid and both decode here.

Open in the full decoder →

Generated from the FIX 4.4 dictionary and verified at build time: it parses and validates with no issues. Open the decoder to try your own message.

Where tag 259 appears

Requiredness is a property of the message, not of the field: the same tag can be optional in one message and conditionally required in another.

Message	MsgType	Requiredness	Where in the message
ExecutionReport	8	Optional	directly on the message body

Wire format

A calendar date in the market's local timezone, with no time component and no offset. @boarteam/fix keeps the value as a string; format rules are checked by validate(), which reports validate/invalid-value rather than throwing.

Read tag 259 in TypeScript

decode.tsts

import { createFixEngine } from "@boarteam/fix";import { dictionary } from "@boarteam/fix-dict-fix44";const fix = createFixEngine(dictionary);const { message, issues } = fix.parse(raw);const field = message.fields[259];field?.name;   // "BasisFeatureDate"field?.raw;    // the verbatim wire stringfield?.value;  // coerced to a string

Decode this in your own code

The same engine that produced the decoded example above is an Apache-2.0 npm package with zero runtime dependencies. It runs in Node and in the browser, and parse() returns problems as data instead of throwing.

npm i @boarteam/fix @boarteam/fix-dict-fix44

Try the decoder Source on GitHub